Conventional letter trays for desk top use are provided with means for stacking or tiering the trays one upon another but the stacking means has in some cases been unsightly, and in other cases difficult to manipulate, or both, and often the attaching means are complicated and expensive. Trays or file troughs for holding letters and envelopes in vertical position have been provided for desk top use, but those with which we are familiar are adapted only for use as separate units and have not been adapted for use in multiples or attached to a tiered letter tray.